The present invention relates to a device for actuating two outlet valves, which are acted on via a valve bridge, of a valve-controlled internal combustion engine for motor vehicles.
From US 2010/319657 A1, for example, it is known for the braking action of an internal combustion engine in the overrun mode to be intensified by virtue of the exhaust-gas backpressure having a decompression action superposed thereon by a pressure flap in the exhaust tract (EVB or exhaust valve brake), wherein at least one outlet valve per cylinder of the internal combustion engine is held open in an intermediate position in the braking mode. This is realized in the valve drive of the internal combustion engine by a hydraulically charged piston-cylinder unit in the force flow between the driving cam of the camshaft and the actuation element which acts on the outlet valve, or a rocker arm. There is also arranged in the actuation element a second piston-cylinder unit which acts as a hydraulic valve play compensation element (HVA) such as is known per se.
Furthermore, from DE 10 2008 061 412 A1, a generic device is known in which two outlet valves per cylinder of the internal combustion engine are actuated by means of a valve bridge, wherein, by means of two hydraulically charged piston-cylinder units in conjunction with a positionally fixed counter bracket, one of the two outlet valves is held open during engine braking operation. Furthermore, a hydraulic valve play compensation element (HVA) is provided which ensures play-free valve actuation during normal engine operation.